The photographs struck the web with the force of thunder. Early Monday afternoon Beijing time, pictures emerged of what appeared to be a fiery crash in central Beijing, showing a vehicle ablaze at the north end of Tiananmen Square, a black plume of smoke rising just feet from the over-sized portrait of Chairman Mao. Rumors swirled: Could this be an accident? Was it a terror attack? A self-immolation? Police confirmed the crash, but said little else. Five people were dead in total, three of them in the jeep. At least 38 others in the square had been injured, according to Xinhua, China’s government-controlled newswire. The city waited for more details.

We’re still waiting. So powerful are China’s crowd and information control that hours after the incident, basic details are left unknown or obscured. Officials confirmed that a car veered into a crowd, leading to death and injuries. Beyond that: nothing. Online, it was a different story. Images posted on social media and blogs showed the SUV completely engulfed in flames, smoke visible hundreds of meters away. But authorities made quick work to contain the situation. By mid-afternoon the square was barricaded, with a line of security officials blocking all pedestrian traffic. Police officers told bystanders, including many tourists, to turn and walk the other away. A plainclothes agent used a handheld video camera to film those who lingered near the gate.

Whether by accident or act of protest, the car struck China’s literal and symbolic heart. This is the very center of the capital: To the north lies the Forbidden City, the old imperial palace, which today is one of the city’s top tourist destinations. To the west sits the Great Hall of the People, the seat of parliament, as well as Zhongnanhai, the closely-guarded compound that houses the country’s top leaders. Mao’s mausoleum lies to the South.

The square is also a symbol of resistance. It was here that students gathered in 1989 to call for political reform—and here that they were killed. Information about what happened that summer is still carefully censored, as, quite often, is the word ‘Tiananmen’ itself. A man set himself alight in the square in 2011, amid a string of fiery protests in China’s Tibetan areas. In 2003, another man, despondent over being forcibly located, survived a similar attempt. If you want to run afoul of China’s security apparatus, head to the square with a political placard or a news camera. It may be the most-guarded place in China.

With little information to go on, China’s micro blogging sites were rife with speculation, and, as is common, black humor. “Perhaps they could not see the guardrail because of the smog,” joked one netizen. “They should have hit the portrait on the wall,” said another.

Few believe it was an accident, but there is no hard evidence either way. And that probably won’t change: By early evening, the dramatic photographs started disappearing from the web—scrubbed, it seems, by China’s censors.